1. Field of the Disclosure
The present disclosure relates to processes for testing regions and forming electronic devices, and more particularly to processes for testing a region for an analyte, and optionally, forming an electronic device after testing the region.
2. Description of the Related Art
For x-ray fluorescence spectrometry (“XRF”), when subjected to a primary x-ray flux, analyte atoms on a surface of a silicon substrate absorb the energy of the primary x-ray photon and undergo the process of fluorescence, which results in the emission of a secondary fluorescent x-ray at an energy that is characteristic of the analyte atom. The identity of the analyte atom may be determined by measuring the energy of the fluorescent x-ray photon and the intensity of the photons at that characteristic energy.
In total reflection x-ray fluorescence spectrometry (“TXRF”), the primary x-ray beam strikes a silicon substrate at a very low angle (less than 1°), almost parallel to the surface. At this very low or “grazing” angle, a phenomena termed “total reflection” occurs and the x-ray beam, which would normally penetrate through the entire silicon substrate if the primary x-ray beam would strike the silicon substrate perpendicular to the surface, reflects off the surface, interacting with only the outermost 5 to 10 nm of the substrate surface. A strong fluorescence emission signal is detected due to the presence of the silicon within the substrate. The fluorescence emission signal for silicon is so strong that the ability to detect some analytes is significantly reduced.
In one attempt to solve the problem related to the strong fluorescence emission for silicon includes removing the silicon substrate background fluorescence by depositing liquid samples onto polycarbonate disks for subsequent analysis by TXRF. This suffers for the disadvantage that the tool-level analyte monitors must be subjected to a pretreatment technique, such as a vapor phase decomposition prior to the TXRF analysis. In addition to the added expense and time required for this pretreatment, all areal distribution information concerning the analyte is lost.
Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the invention.